Brush head for a sonic or ultrasonic toothbrush and toothbrush

ABSTRACT

The invention relates to a brush head with an integrated ultrasonic transducer and with a plurality of bristle tufts that are arranged on a baseplate and can be caused to vibrate by the ultrasonic transducer during operation, wherein the bristle tufts are arranged in a plurality of substantially parallel rows aligned symmetrically relative to a central longitudinal axis or central plane of the baseplate, wherein a first row and at least one second row are provided in the transverse direction as viewed from the central longitudinal axis or central plane, and wherein all bristle tufts of a row are the same length. Such a The brush head is to be improved so that a particularly thorough and reliable cleaning of the teeth is possible when a fixedly installed brace is present. For this purpose, the bristle tufts of the second row are designed according to the invention to be longer than the bristle tufts of the first row.

BACKGROUND OF THE INVENTION

The invention relates to a brush head for a sonic or ultrasonic toothbrush with a plurality of bristle bundles, which are arranged on a base body or on a base plate, wherein during operation the plurality of bristle bundles are set into oscillations by the ultrasonic generator.

During cleaning of a permanently installed brace, such as a multi-band or multi-bracket apparatus, by means of an electric toothbrush, there is a tendency of insufficient cleaning performance around the base of the bracket. The mesiodistal areas beneath the arch and the tooth sections to the side of the bracket edges “in the slipstream” of the bracket corners do not become fully free of plaque even in the case of intensive cleaning, since no contact takes place here between the bristles and the bracket and/or the tooth. This is due to the rotary motion of the brush head that normally takes place with electric toothbrushes and also due to the shape of the brush head (length and orientation of the bristles).

Besides conventional electric toothbrushes, in which either the entire brush head support swings back and forth or the brush head oscillates or vibrates, so-called ultrasonic toothbrushes have been known for some time, in which an ultrasonic generator integrated in the brush head sets the flexible bristles, normally grouped in bundles, into high-frequency oscillations. The advantage of such ultrasonic toothbrushes, in addition to the thorough cleaning, is that the teeth and gums are mechanically stressed only to a small degree. For this to occur, a special ultrasonic toothpaste is necessary. Also, the cleaning procedure must be modified in comparison with conventional electric toothbrushes to achieve an optimal cleaning effect. In the case of ultrasonic toothbrushes it is generally recommended to first distribute the ultrasonic toothpaste on the inner and outer surfaces of the teeth, while the toothbrush is still switched off. Then the tooth brush is switched on and the brush head is held for five to ten seconds on the respective inner and outer surface, without performing a mechanical back-and-forth motion of the entire brush head (i.e. no “scrubbing” of the teeth).

The tooth cleaning problems described above in connection with conventional electric toothbrushes in the case of a permanently installed brace exist in a similar manner, although less critically, in the case of ultrasonic toothbrushes.

It is an object of the invention to present a simply constructed and easily manufacturable brush head for a sonic or ultrasonic toothbrush (as well as a toothbrush including such a brush head), which is especially suitable for cleaning a brace of the multi-band/multi-bracket type and which avoids the aforementioned problems.

“Bristle length” is to be understood in the following as the length of the section of the bristles protruding freely from the outer side of the base plate without taking into account a root or base section of the bristles extending into a base plate and possibly continuing on the back side toward the ultrasonic transducer. In the event that the length of the bristles varies slightly in a bristle bundle arranged inclined to the base plate, “length of the bristle bundle” is to be understood as the average bristle length of the bristles of that bundle. The bristle bundles together constitute a bristle bundle arrangement.

SUMMARY OF THE INVENTION

The embodiment according to the invention offers the advantage that the brush head and/or its bristle bundle arrangement, due to the reduced height of the inner bristle bundle row(s), can easily pass over a wire arch and over the brackets of a permanently installed brace. The shorter inner bristle bundles clean the wire arch and the areas on the brackets. Due to the outer, longer bristle bundle easily reaching the tooth surface, cleaning all around the bracket base is achieved.

In the following it is assumed that the ultrasonic toothbrush head and/or the bristle bundle arrangement—at least with respect to the bristle configuration and the outer form of the base plate supporting the bristles—is designed to be altogether mirror symmetrical to a middle or longitudinal section plane containing a middle longitudinal axis of the base plate. It is therefore sufficient to view only one of the two halves of the ultrasonic toothbrush head, respectively. Logically, the rows of the bristle bundles are numbered one, two, three, etc. starting from the middle longitudinal axis or from the middle plane containing this axis. When viewing the ultrasonic toothbrush head altogether one can of course also refer to an inner, middle or outer row.

Instead of one first row respectively for each brush head half, i.e. a total of two inner rows separated from each other by a distance, a total of only one inner row of bristle bundles could be provided, half of which crosswise to the longitudinal extension of the row are allocated respectively to one of the two bristle head halves. Such an embodiment is likewise the subject of the invention and is included in the wording of the claims.

In the invention, it is expedient if the bristle bundles of the first row stand perpendicular on the base plate. The free ends of the bristles of the bristle bundles belonging to the first row are in a common plane, or essentially in a common plane, oriented parallel to the base plate.

In a preferred embodiment of the invention, the bristle bundles of the second row are inclined inwardly, i.e. toward the middle plane, namely with the advantage for example that the inclined, longer bristles of the second rows flanking or lining the inner row(s) with the shorter bristles reach into the corners directly around the bracket base and into the area beneath the wire arch and clean the tooth surface located there as a result of the direct contact when the brush head is passed over the wire arch and the brackets of a brace permanently installed on the teeth.

To achieve the aforementioned purpose it has proven effective if the angle of inclination of the bristle bundles of the second row relative to the base plate or a reference plane oriented perpendicular to the bristle bundles of the first row(s) is in the range between 65° and 85°, preferably in the range between 70° and 75°, especially preferably about 73°.

Outside of the second row, there is provided a third row of bristle bundles, which stand perpendicular to the base plate or to the reference plane or likewise are arranged on the base plate inclined inwardly toward the middle plane, namely preferably at the same angle of inclination as the bristle bundles of the second row.

It is advantageous if the bristle bundles of the third row have the same or essentially same height above the base plate as the bristle bundles of the second row, so that the ends of the bristle bundles of the second and third row irrespective of any “micro-structuring” or length differentiation within the single bristle bundles lie within a common plane oriented parallel to the base plate or to the reference plane.

In general, it is also advantageous if the free bristle ends of the angled, i.e. inclined bristle bundles, are cut so that they lie in a common plane oriented parallel to the base plate, so that the aforementioned “micro-structuring” is not present.

Advantageously, each of the rows comprises six to eight, preferably seven bristle bundles. It can also be advantageous if the outer rows for example have one or two more or fewer bristle bundles than the inner rows. The distance between two bristle bundles of one row, i.e. viewed in longitudinal direction, is in the range of 2.5 mm to 4.0 mm and preferably about 3.5 mm.

The distance between the adjacent rows, i.e. viewed in crosswise direction, is in the range of 2.0 mm to 3.0 mm and preferably is 2.5 mm.

The bristle bundles of the first, inner row(s) preferably have a length in the range of 3 mm to 5 mm, preferably 4 mm, which in the case of perpendicular orientation corresponds to their height above the base plate.

The bristle bundles of the second, i.e. middle or outer tow(s), preferably have a length in the range of 6 mm to 10 mm, especially preferably 7 mm to 9 mm, which in the case of perpendicular orientation corresponds to their height above the base plate, and which in the case of inclined orientation corresponds to a correspondingly reduced height (length x sinus of the angle of inclination). For example, a 7 mm long bristle bundle at an angle of inclination of 73° would have a height of about 6.7 mm.

The ratio of the length of the short, inner bristle bundle to the length of the longer, middle or outer bristle bundle is accordingly preferably in the range of 0.3 to 0.8 and especially preferably about 0.5 to 0.6. The bristle bundles of the third, i.e. outer row, are adapted in the above manner to the bristle bundles of the second row with respect to their length.

The aforementioned lengths are selected so that on the one hand the shorter inner bristle bundles reliably reach closely enough to the brace elements and on the other hand that intermeshing of the bristles of the longer bristle bundles is avoided, with good transmission of the ultrasound. The result of intermeshing of the bristles would be that the action of the bristles on the brace elements or the tooth would no longer be straight; instead, the ultrasound would radiate at undefined angles, which is undesirable.

The bristles of the brush head and/or the base plate can be made of plastic, for example. As an electro-mechanical transducer or ultrasonic generator, a piezo element can be used that can generate oscillations at a frequency interval from, for example, from 30 Hz up to at least 30 KHz. The bristles are preferably designed and attached to the ultrasonic generator so that their free ends are deflected axially and/or laterally by the ultrasonic generator.

The brush head can be attached or formed onto a brush head support in the conventional manner. The brush head support can be designed for example as a plug-in element for a handle element, which in the known manner accommodates rechargeable batteries and suchlike for supplying the operating voltage for the ultrasonic generator as well as suitable control elements such as buttons or switches, as well as any other electronic components. Accordingly, an electric and mechanical coupling can be provided between the brush head support and the handle element.

The term “essentially” or “approximately” as used in the invention means deviations from the exact value by +/−10%, preferably by +/−5% and/or deviations in the form of changes that are insignificant for the function.

Further embodiments, advantages and possible applications of the invention are disclosed by the following description of exemplary embodiments and the drawings. All characteristics described and/or pictorially represented, alone or in any combination, are subject matter of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described below based on exemplary embodiments with reference to the drawings, in which:

FIGS. 1 and 2 show a brush head according to the invention in different perspective views;

FIGS. 3 and 4 show the brush head of FIGS. 1 and 2 in schematic side and front view;

FIG. 5 shows a schematic representation in top view of the top side and/or the bristles of the brush head of FIGS. 1 and 2;

FIG. 6 shows, in an enlarged cross sectional view, the base body of the brush head of FIGS. 1 and 2 in the area of a bristle bundle.

DETAILED DESCRIPTION OF THE INVENTION

The brush head 2 of an ultrasonic toothbrush 1 depicted in the drawings in a preferred embodiment comprises a base body 4 with a predominantly rectangular solid form manufactured from a plastic and having rounded corner and edge regions. On one side, which in the depiction in the drawings is the top side of the base body 4, the base body 4 is designed with a predominantly rectangular, elongated base plate 6 that is flat on its top side and has rounded corners. On one of the two end sides the brush head 2 continues in its lengthwise direction or middle longitudinal axis L in a brush head support or handle element 7 molded or connected to the brush head. The top side of the base plate 6 lies in a reference plane EB.

In the base plate 6 there is embedded a regular grid or array of essentially circular receiving openings 8, in which one bristle bundle 10 consisting of a plurality of bendable and flexible bristles 12, for example plastic bristles, is respectively accommodated and anchored. In the interior of the base body 4, on the back side or bottom side of the base plate 6 is a flat ultrasonic generator 14, only schematically suggested in the drawings, which can also be referred to as an electro-mechanical ultrasonic transducer and which during operation excites the bristles 12 of the bristle bundles 10 to oscillations with oscillation frequencies above 300 Hz and up to 1.6 million oscillations per minute or 30 KHz and more. A ferro-electric ultrasonic transducer or a piezo actuator can be used as the ultrasonic generator 14, for example. The technical details are known to persons skilled in the art and require no further explanation here.

The brush head 2, with respect to its bristles consisting of the bristle bundles 10, is adapted specifically to cleaning requirements for a permanently installed brace, especially of the multi-band or multi-bracket type. For this purpose the brush head 2 is symmetrical in design to a middle or longitudinal section plane M containing the middle longitudinal axis L of the base plate 6. The bristles and/or the bristle bundle field consists of a plurality of rows R1-R3, i.e. six in the depicted embodiment, of bristle bundles 10 extending essentially parallel to the lengthwise direction L. Each row R1-R3 comprises seven bristle bundles 10 arranged at the same longitudinal distance a=3.5 mm from each other. The distance b=2.5 mm between two adjacent rows R1-R3 in a crosswise direction Q, i.e. in an axis direction perpendicular or essentially perpendicular to the middle axis M, is likewise the same for all rows R1-R3. The bristle bundles 10 additionally align row-by-row in crosswise direction Q, so that altogether a regular rectangular grid of six times seven bristle bundles 10 is implemented. The first, i.e. inner, row R1 when viewed from the middle plane M in crosswise direction Q comprises perpendicular to the base plate 6 and/or the reference plane EB upright bristle bundles 10 with a length or height of about 4 mm. The free bristle ends of the bristles 12 are expediently rounded, to prevent injury to the sensitive gums.

The second, outwardly successive row R2 on the other hand comprises bristles 12 and/or bristle bundles 10 inclined inwardly toward the middle plane M and having a length of about 7 mm. The bristles 12 and/or bristle bundles 10 on their free ends are at a smaller distance from the middle plane M than in the area of the base plate 6. The corresponding angle of inclination a between the longitudinal extension of the bristles 12 and/or bristle bundles 10 and the reference plane BE oriented perpendicularly to the middle axis to the top side of the bristle body 4 or base plate 6 is about 73°. In deviation from the graphical depiction in the drawings, the angled bristles of the second row R2 can be cut so that their free ends lie in a common plane.

Additionally, provided on the outside is a third row R3 of bristle bundles 10, which and/or whose bristles 12 stand perpendicular or essentially perpendicular on the base plate 6 and/or the reference plane EB. The bristle length is preferably selected so that the free ends of the bristles 12 of the third row R3 and the free ends of the correspondingly cut bristles 12 of the second row R2 lie in a common plane. The bristle length of the bristles 12 of the bristle bundles 10 of the third row is then somewhat less than 7 mm.

Alternatively, the possibility also exists that the bristle bundles 10 of the third row R3 likewise are inclined inward relative to the base plate 6 or the reference plane EB at the angle α, for example at the angle of 73°, so that the bristles 12 and/or bristle bundles 10 on their free ends then likewise are at a smaller distance from the middle plane M than in the area of the base plate 6. Corresponding to the mirror symmetrical design of the bristle field the three rows R1-R3 are provided on both sides of the middle plane M, so that the bristle field is implemented altogether with six times seven bristle bundles 10.

In a further embodiment, instead of the two inner rows R1 of relatively short bristle bundles 10 arranged on both sides of the middle plane M and symmetrical to the latter, only one single such row R1 is provided, whose bristle bundles 10 are arranged along the middle longitudinal axis L or the middle plane M. Therefore, in this embodiment for example one bristle field with a total of five times seven bristle bundles 10 is implemented.

Furthermore, also fewer or more than seven bristle bundles 10 can be provided for each row R1-R3 in the direction of the middle longitudinal axis L. In the case of a short brush head 2 that is desirable for some applications, four or five bristle bundles 10 for each row R1-R3 may be sufficient, for example. Further it is also conceivable to implement an especially wide brush head 2 with a fourth or fifth row of bristle bundles 10. Finally, it is possible that some of the rows, especially the outer rows, are not oriented exactly parallel to the middle longitudinal axis L or middle plane M, but instead are slightly angled. For special purposes an asymmetrical design can also be considered.

The brush head 2 according to the invention, which for example is provided removably on a handle element 16, is used in principle in the same manner as known brush heads of ultrasonic toothbrushes, namely as follows:

-   -   distribute ultrasonic toothpaste lightly on the insides and         outsides of the teeth,     -   then hold the bristles 12 on the teeth from the inside and         afterwards from the outside with the ultrasonic generator 14 or         handle element 16 switched on, namely for five to ten seconds         without moving and     -   then change the treatment location, i.e. hold the bristles 12 on         the next teeth.

The brush head 2 according to the invention, as a result of the “gap 17” in the bristle field, passes over the wire arch and the brackets of the permanently installed brace. The outer, longer and possible also angled bristle bundles 10 achieve cleaning under the wire arch and around the bracket base. The shorter inner bristle bundles 10 clean the wire arch and the surfaces on the brackets.

The brush head 2 according to the invention therefore ensures altogether optimal cleaning of the hygiene-critical bracket region.

REFERENCE LIST

1 sonic or ultrasonic toothbrush

2 brush head

4 base body

6 base plate

8 receiving opening

10 bristle bundle

12 bristles

14 ultrasonic generator

16 handle

17 gap

L longitudinal direction

M middle plane

R1, R2, R3 row

Q crosswise direction

EB reference plane

a lengthwise distance

b crosswise distance

α angle of inclination 

1. A brush head for a sonic or ultrasonic toothbrush, comprising: an ultrasonic generator and a plurality of bristle bundles, which are arranged on a base plate and during operation are set into oscillations by the ultrasonic generator, the plurality of bristle bundles being arranged in a plurality of rows oriented essentially parallel and symmetrical to a middle longitudinal axis of the base plate, at least one first row of bristle bundles and thereon adjoining at least one second row of bristle bundles provided in a crosswise direction to the middle longitudinal axis, the plurality of bristle bundles in each row being of a same length or essentially the same length, the plurality of bristle bundles of at least one second row of bristle bundles being longer than the plurality of bristle bundles of the at least one first row of bristle bundles.
 2. The brush head according to claim 1, wherein the plurality of bristle bundles of the at least one first row of bristle bundles stand perpendicular on a reference plane of the base plate.
 3. The brush head according to claim 1, wherein outside of the at least one second row of bristle bundles at least one third row of bristle bundles is provided, and the bristle bundles of the at least one third row stand perpendicular to a reference plane of the base plate and/or are of a same length as the bristle bundles of the at least one second row.
 4. The brush head according to claim 1, whereby on both sides of the middle longitudinal axis the at least one second row of bristle bundles and/or at least one third row of bristle bundles is provided.
 5. The brush head according to claim 1, wherein the bristle bundles of the at least one second row stand perpendicular to a reference plane of the base plate or are inclined toward the middle longitudinal axis.
 6. The brush head according to claim 3 wherein the bristle bundles of the at least one third row stand perpendicular to the reference plane of the base plate or are inclined toward the middle longitudinal axis.
 7. The brush head according to claim 5, wherein an angle of inclination of the bristle bundles of the at least one second row relative to the reference plane of the base plate is in a range between 65° and 85°.
 8. The brush head according to claim 3, wherein the bristle bundles of the at least one third row are arranged at a same angle of inclination on the base plate as the bristle bundles of the at least one second row.
 9. The brush head according to claim 3, wherein the bristle bundles of the at least one third row are at essentially a same height above the base plate as the bristle bundles of the at least one second row.
 10. The brush head according to claim 1, wherein free brush ends of inclined bristle bundles are cut so that they lie in a common plane.
 11. The brush head according to claim 1, wherein each of the at least one first row of bristle bundles and the at least one second row of bristle bundles comprises from six to eight bristle bundles.
 12. The brush head according to claim 1, wherein the bristle bundles of the at least one first row have a length in the range between 3 mm and 5 mm.
 13. The brush head according to claim 1, wherein the bristle bundles of the at least one second row have a length in the range between 6 mm and 10 mm.
 14. The brush head according to claim 1, wherein a distance between adjacent rows of bristle bundles viewed in crosswise direction is in the range of 2 mm to 3 mm.
 15. (canceled)
 16. The brush head according to claim 6, wherein an angle of inclination of the bristle bundles relative to a reference plane of the base plate is in the a range between 65° and 85°. 